To me, this is the most interesting Imperial Japanese Navy Longines Weems.
It was from the famous Genda's Blade Squadron 343. It's worth looking up who made up Genda's Blade. This was the most elite squadron of the entire Pacific Theater. Until the Americans developed the Corsairs and Hellcats, no combat fighter group could come back winning a mission against 343. This group was known to purposely fly loops over the American bases taunting the Americans to come out to play. The Americans could not out fly the 343 Kokutai in dog fights. Even with the most advanced fighters in the Pacific, at dog fights the 343 was too good. Instead the Allied forces had to use hit and run tactics to use speed and surprise to begin winning against the 343 to avoid direct fights against the aces of 343. 
The below watch was recovered from a wreak of a three seater Saiun reconnaissance plane so fast it out flew all aircraft including interceptors. There is a memorial where the mid air collision occurred built with parts of the aircraft by the locals.






My watch is from the same batch. Assigned to night missions, a night reconnaissance flight was among the most difficult and dangerous missions. Only two remaining in the world today with a night missions dial.
Caseback is the black strap one in middle. It has the Imperial Japanese Navy Sky Warrior issue number #827. 
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